Telephone with a push-button impulse sender



May 7, 19574 J. F. HOUDEK, JR

TELEPHONE WITH A PUSH-BUTTON IMPULSE SENDER original Filed April 12,1952 TO SWITCHBOARD Aillanlilv lili. l(

Nm 2925 NZSUNXN .mi

United tates Pat-fem Joseph F. Hondek, Jr., Eimhurst, Ill., assignor toInternational Telephone and Telegraph Corporation, a corporation ofMaryland Original application April 12, 195,2, Serial No. 281,997,

116W Patent No. 2,749,388, dated June 5., 1956. D1- vided and thisapplication December 23, 1955, Serial 2 Claims. (Cl. 179-90) Thisinvention relates to a telephone with a push-button impulse sender. Itsprincipal object is to provide a new and improved telephone having asimple and economical arrangement for responding to the operation of anyone of a number of push-buttons to transmit respectively correspondingtelephone line numbers.

This application is a division of my prior application for An AutomaticIntercommunication Telephone System, Serial Number 281,997, tiled April12, 1952, now Patent No. 2,749,388.

Thel telephone set disclosed herein is of the push-button type and isarranged for use in telephone systems of the type shown in my priorapplication wherein a separate selector is employed for each line. Insuch systems, to maintain a low cost per line, economies must be presentin the station apparatus as well as in the selector apparatus.

Heretofore, in telephone sets wherein the calling of desired `linenumbers was controlled by push-buttons rather than by the usualtelephone dial mechanism, it was customary to employ motor-drivendevices to transmit impulses characteristic of a desired line. Ingeneral, motor-driven devices, in addition to being cumbersome, arequite expensive and accordingly nd little application in systems of theforegoing character.

According to the present invention, economies in pushbutton-controlledimpulse-transmitting devices are realized by the employment of a simpleand economical switching mechanism which is controlled by simple relayinterrupter arrangement.

Several features of the telephone set here employed reside in thecontrol circuit arrangement for controlling the starting and stopping ofthe switch mechanism and in the arrangement for controlling the numberof impulses transmitted according to the line selected by push-buttonoperation.

The above-mentioned and other features and objects of this invention andthe manner of attaining them will become more apparent, and theinvention itselj:` will be best understood, by reference to thefollowing description of an embodiment of the invention taken inconjunction with the accompanying drawing wherein Fig. 1 showsa'pushbutton controlled telephone station or executive station S2connected to the selectors of the switchboard shown in my priorapplication by two conductors L, and S and supplied by power overconductors G, de,V and Station S2, being of the loud-speaking type,includes` a microphone pickup. unit 201 and a loud-speaker unit 202connected to respective transmitting and receiving amplifiers In Placeof the. conventional dial, the executive station is equipped with apush-button calling device corn,- prising buttons 1 to 20 of device205.., together with a stepping selector SEL-200. and associated relays.Device 205 also includes an answer key A and a disconnect key Off which.cooperate. with. kerst to 20 in Controlling the line in lieu of theusual hnnkswitch.- Executive station S2 includes a ringing push-button204 for signalling called lines and a signal buzzer 239 for servingas'vthe executive station ringer.

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The operation of executive station S2 on line L2 in ex tending a call toa desired other line (not shown) will now be described.

The party at any executive station S2, to call another line, depressesthe push button corresponding to the desired line to be called and waitsfor the party at the called line to answer, as the rin-ging operation isfully automatic.

Assuming push button 1 is depressed, it is mechanically engaged and heldin a depressed condition by retaining bar 206. Contacts of push button 1remove ground potential from the winding of normally operated startrelay 238, restoring it. Contacts 1 and 2 of relay 238 transfer lineconductor L from buzzer 239 to the microphone and loud-speaker amplifiercircuits, and its contacts 3 extend ground potential to. the windings ofinterrupter relay 236 and hold magnet 234.

Contacts 2 of relay 238, in addition to connecting the amplifiers toline conductor L", extend ground potential through resistor 223 and coil222 to line conductor L from whence it is extended to the selector unitassociated with the line to which station S2 is assigned and preparesfor its operation responsive to control from executive station S2.

At the same time, hold magnet 234 Operates from ground at contacts 3 ofrelay 238 and its makes contacts extend suc-h operating ground to brush221 of selector SEL-200 in preparation for automatically signalling thedesired called station at the proper time. Armature 251 of magnet 234 isactuated against the light tension of its restoring spring 254 andreleases latch 252, which is moved by its light tension spring 253 intoeffective holding engagement with the teeth of rack 233, therebypreparing selector SEL1200 for operation.

Also, at the same time, interrupterl relay 236 operates from the. groundat break contacts 3 of now-restored start relay 238 and at its makecontacts extend ground to the winding of stepping magnet 235, operatingit. Contacts 2 of stepping magnet 235 open the operate circuit of theinterrupter relay, which restores a short time later to. restorestepping magnet 235i. With the restoration of magnet 2,35, the operate.circuit of the interrupter relay is again closed and the` sequentialoperation and, restoration of relay 236 and magnet 2.3.5. is repeated.This cycle of interrupter relay and stepping magnet Operation andrestcraton continues until stop relay .237 operates, to open the operatecircuit of interrupterrelay 235.

With each impulse transmitted to the battery-connected winding ofstepping magnet 2.35. from` contacts, of relay 236, stepping magnet 2.35QperatesA its armature 225 against the tension of restoring spring 256.'Eachl time armature 225 is actuated, its pawl 259 engagesl theassociated tooth to advance rack 233v and brushes 221 and 2.31-, oneStep.l Brushes 22,1 and 2 31 are thereby caused to move from theirillustrated normal position Iinto engagement with the switch contactssuccessively, thereby becoming successively connected with the contactsof push buttons 1 to 20 over their respective wires 1to1/to, 280. After.cach step, brushes 2.2.1. and 231 are heldv ntheir advanced position bythe engagement of latch- 252, with the teeth of rack 233.

When all. push buttons are iny restored condition. (as illustrated),ground is extended to the winding of start relay 238, holding itoperated.V Upon the depressing of one of the push buttons correspondingto a dcsil'ed line, ground is removed from the Winding of relay 233, aswell as from each of the wires 261, to 281 which are associated with thepush buttons,V following theV one. which was depressed. Thus, as brush231 advances across the switch contacts associated with the wires 261H1280, ground is extended thereoverfrom each wire, up to and including,the wire corresponding tothe push button depressed. Brush 231 thereaftercontinues advancing but without contacting ground potential on theremaining wires.-

Since the desired line called is assumed to be the first line, and pushbutton 1 ot push-button assembly 205is depressed, ground potential is`removed fromY wires 262 to 281, which are associated with the remainingpush buttons 2 to 20. Brush 231 of unit `SEL-200, advancing across theswitch contacts associated with wires 261 to 280, contacts ground onwire 261 and no others, and in conjunction with contacts 1 of steppingmagnet 235, transmits one impulse to the stepping magnet (not shown) ofthe switchboard selectors to control it to make connection with thecalled line which corresponds to the push button depressed.

lf the called line is busy, ringing potential is applied tothe calledline but is ineiective. After the completion of the ringing period, busytone is returned to station S2. If the called line is idle, the calledstation is effectively signalled as will be described.

As brush 231 of selector unit SELt) passes the last switch contactassociated with the push buttons, grounded brush 221 makes Contact withringing bar 224 which is connected to line conductor L of line L2through contacts on relay 233. Responsive to the transmission of groundto conductor L' through contacts on relay 238, operations occur `asdescribed in my prior application which energizes the buzzer at thecalled station to signal the called party on the called line, suchbuzzer being connected to line conductors through the usual hookswitchor in the manner in which the executive station buzzer is connected. Thebuzzer of the called station is energized as long as brush 221 is incontact with ringing bar 224 and may, for example, extend over a periodof several interruptor cycles.

After advancing beyond ringing bar 224, responsive to the continuedoperation :and restoration of stepping magnet 235, grounded brush 221makes contact with stop bar 225 which is directly connected to thebatteryconnected winding of stop relay 237,` thereby operating it.Contacts 2 of relay 237 open the operate circuit of interrupter relay236, thereby stopping the advancement of stepping relay 235. Contacts 3extend positive battery potential to the amplifiers, preparing them foruse. The calling party at station S2 awaits answer by the called party,or a busy-tone signal in the event that the called line is busy, suchbusy tone being returned to the calling party through the loud-speakeramplier.

If the called party fails to answer responsive to the automatic ringing,an additional ring signal may be provided manually by depressing ringbutton 204 which applies ground through resistor 220 directly toconductor L' of line L2. Thus, the line of the called party may bemanually rung until answered.

Voice signals from the calling party, after the called party answers,are fed to transformer 209 from transmitter 201 and then passed throughvolume control 210 to the iirst grid of the dual-triode amplifier tube211. The output of amplifier tube 211 is coupled by condenser 212 to thecenter-tapped transformer 214 and inductively coupled to line conductorL. The microphone output is divided at the transformer center-tap, by abalanced network including artificial line 213, to cancel anyreproduction (howling) by the 'loud-speaker of signals from themicrophone. The `amplified signals from the microphone amplifier aretnansmitted to the called line over the connections established by theselector unit associated with the calling station S2.

Return signals from the called line are fed to impedance-matchingtransformer 215 through coupling condenser 216, and are inductivelycoupled to the grid of the cathode-biased xamplifier tube 218 throughvolume control potentiometer 217. The output of amplifier tube `21S isinductively coupled by transformer 219 to loudspeaker 202 whichreproduces the transmitted signals. r

The `feed-back signals between loud-speaker 202 and microphone 201are'cancelled by the use of farticial 238, operating it. Contacts 3 ofrelay 238 disconnect ground potential from the winding of hold relay234, releasing it. The release of hold magnet 234 disengages pawl 252thereby permitting brushes 221 and 231 to be returned to their normalillustrated position by a returning spring, not shown. y

Relay 208, serving to release any operated push button, functions lasdescribed in my prior application under control of a regular station(not shown) which may be associated with the executive station S2.

Withe brush 221 in its restored position, the operating and hold circuitof stop relay 237 is opened and it restores. Its contacts 3 removepositive battery potential from the amplifiers, thereby returning themto normal condition. Contacts 1 disconnect the amplifiers from lineconductor L and open the holding circuit of the switchboard selector(not shown). The calling lines L2 and the called line are now in an idlecondition and in readiness for originating or answering another call.

When line L2V is called, buzzer 239 is energized from ground onconductor L1 appearing through contacts 1 of relays 237 and 238. Thecall may be answered at executive station S2 by depressing answer pushbutton A ofpush-button assembly205. Contacts of push but.- ton A extendground potential to the winding of stop relay 237, energizing it. Ashereinbefore described, the operation of stop relay 237 disconnectsbuzzer 239 and causes the amplifier circuits to be energized andconnected to the calling line. Conversation may be carried on with thecalling party over the executive station unit as previously described. v

Upon completion of the conversation, push button Ol of the push-buttonassembly 20S-is depressed andk disengages the answer button, therebyrestoring stop relay 237 and returning the executive station apparatusto normal idle condition.

While I have'described above the principles of-myinvention in connectionwith specific apparatus, it is tobe clearly understood that thisdescription is made only by way of example and not as a limitation tothe scope of my invention.

I claim:

1. In a telephone station for use on a line of an auto: matic switchingsystem, a start relay, digit-marking conductors, digit keys associatedrespectively with said conductors, means responsive to an actuation ofany said digit key for placing a corresponding digit-marking conditionon saidconductors and for causing an operation of said start relay, asending-start wire, means responsive to said operation of the startrelay for imposing a calling condition' on the said line and forenergizing said start wire, a stepping switch having access to saiddigit-marking conductors, a stepping magnet and an interrupter relay forsaid stepping switch, means responsive to the said energization of saidstart wire for causing said interruptor relay and stepping magnet tointeract cyclically, whereby the stepping magnet is operated andrestored repeatedly to advance said stepping switch into contact withsaid di'git-markingyconductors successively and to advance beyond thelast one, means responsive to said stepping switch advancing over saidmarking conductors for sendingover said line a number of switch-controlimpulses corresponding to the digit-marking condition thereon, a stoprelay and means for operating it responsive to said stepping switchadvancing beyond said marking conductors, and means including contactson said stop relay for terminating the said interaction of theinterrupter relay and stepping magnet.

2. In a telephone station as set forth in claim l, voicecurrenttransmitting and receiving apparatus and ampliers associated therewithrequiring plate current for their amplifying operation, and meansincluding other contacts 5 of said stop relay for supplying said platecurrent.

No references cited.

